Editors Being Added Without Owner Permission

I run a design agency and we frequently give clients editing access to certain Figma files. I am OKAY to cover a $15 fee for the client, BUT they then add others as editors and I end up paying for 2 other Editor seats. Why is there no process for me to approve or deny these add-ons? It is ridiculous that I get billed for new Editor Seats without being able to approve them first. Any solutions out there!? I am literally paying for people I don’t even know. It’s crazy.